Waste-heat drier



M. J. Il lDE WASTE HEAT DRIER FiledvMay l0. 1923 2 Sheets-Sheet lChrome? 1,513,465 M. J. LIDE WASTE HEAT DRIER Filed MayA 1o.

1923 2 Sheets-Sheet 2 @Huang y Patented @et 28, 1924.

MARTIN J. LIEBE, 0F BIRMINGHAM, ALABAMA.

WASTE-HEAT DRIER. 1

Application led May l0, 1923.

To all w/'Lom t may concern.'

Be it known that I, MARTIN J. Linn, a citizen of the United States ofAmerica, residing at Birmingham, in the county of Jefferson and State ofAlabama, have invented certain new and useful mprovements in VasteHeatDriers7 of which the following is a specification.

My invention relates to a new and improved apparatus for utilizing thewaste heat from bo-ilers or other available sources for the purpose ofeiticiently drying various products suc-h as washed coal preparatory topulverizing lthe same in a suitable mill to produce pulverized fuel.

My invention contemplates the provision of a casing into which the gasescarrying the waste heat are forced under pressure and caused` to passthrough grates carrying the product to be dried.

My invention further contemplates the provision of novel and positivemeans for accomplishing the feed of the product to be dried transverselyacross superposed grates, causing it to How in a comparatively thinsheet in a circuitous path back and forth across the drier casing andthus to be acted on a number of -times by the gases passing through thecasing.

A further feature of my invention consists in the novel arrangement ofchutes at the ends of each grate section which utilize the stack to sealthe-connecting passage between grates, thereby preventing the shortoircuiting of the gases through said passages and forcing the gases topass upwardly through the stock in the grates.

My invention also contemplates a special design of grate adapted topermit the free flow of hot gases through the grates to dry the productresting thereon while prevent ing the escape of the product between thegratesections which are relatively movable to positively feed theproduct resting thereon.

My invention further comprises the novel details of construction andarrangements of parts, which in their preferred embodiment only areillustrated in the accompanying drawings and described in detail in thefollowing specification. f

According to the drawings Fig. 1 is a vertical section through the driercasing proper, the discharge end of the chute and mill being shown inelevation.`

Serial No. 637,982.

F ig. 2 is a side elevation of a portion of the drier casing showing theoperating mechanism for the two lower sets of grates.

F ig. 3 is an end elevation of F ig. 2.

Fig. 4 is a cross-section through a standard grate segment; and

F ig. 5 is a cross-section through a portionl gases under the requisitepressure through' a pipe a into the hopper botto-m 5 of the cleanercasing 6. The gases enter abovethe.-

angle of repose of the dried stock 7 in the hopper and below thelow'estdrying grate. The wet stock enters through an inlet chute 8 atone side of the top 9 of the casing and is delivered by a feed chute 10to the top grate. The grates are preferably of a type adapted to permitthe gases to pass freely upwardly .therethrough tothe stock and also tobe relatively movable for the purpose of positively feeding the stocktransversely of the drier.

In the preferred embodiment of stock drying and feeding grate shown,each grate is composed of a horizontal row of similar rocking gratesegmentsull, all being duplt-` cates and each comprising a top or stocksupporting face 12 provided with closely associated transverse narrowports or slots 13 extending from the axial side of the upper segmentface to itsfree outer edge. From the latter edge extends downwardly acurved guard 14 which subtends an arc of oscilla' tion, that shown beingapproximately 90 and is` connected to or cast integral with supportingwebs or walls 15 that are lntegral with or connected to t-he axial bodyportion 11 of the grate segment. Eachrsegment is provided with endtrunnions 16 which project through openings inthe side walls 17 of thecasing and are mounted in suitable bearings 18 attached to the outerface of said side walls. The horizontal tier of segments composing eachgrate are so closely associated that as a grate segment is rocked aboutits tru-unions to swing its stock supporting surface 12 from horizontalto vertical position, its respective guard portion la maintains so closea clearance with the segment acont thereto that no appiev ciable amountof stock will fall through the grates, it being my desire to have thestock fed back and forth across the casing by the grates so as tosubject it in the most effective manner to the drying action of thegases. rlhe grate segments are operated by the mechanism hereinafterdescribed, the segments composing each grate being connected inalternate groups and the uni-ts of each group being moved oppositely tothose in the other group. The chute 10 stands in such closejuxtaposition to the guard 111C of the adjacent grate segment that thestock will not fall between the chute and segment. The wet stock havingbeen fed across the upper grate falls into a chute. 19 having its bottomjuxtaposed to the adjacent guard of the next lower grate, it being notedthat the guards are disposed towards the chute in this grate. riihestock, having been fed across the secondv grate, is discharged into achute 2O and delivered to the next lower gra-te, which in turn deliveredit to a chute 21. rlhe chute 21 delivers it to the lowest grate, whichin turn delivers it to a chute A single grate segment is disposed atlthe bot-tom of this chute 22 and this segment, as well as the adjacentsegment to each of the chutes above it, acts to support the stock insuch position in the chute as to seal the latter against the by-passingof gases therethrough. This bottom grate segment is connected up foroscillation with one of the segments of the lower grate. rlhe waste heatbearing gases, after being forced up through the grates and the stockthereon, escape through the outlet 23 to a stack or other suitable pointof disposal and the dried stock is fed by a chute 2a, leading from thehopper 5, to a grinding or pulverizing mill 25. which is preferably ofthe ball type and which will act to grind the stock to the requisitepulverized form. for discharge by air blast through the pipe 26, leadingfrom the top of the mill, to any suitable point of consumption.

While it is to be understood that the grates` may be operated by anysuitable mechanism which will cause the segments to feed the stockpositively across the drier, l have illustrated in Figs. 2 and 3 which Inew consider the preferred mechanism for this purpose. Here l show thealternate segment trunnions of the two lower grates having cranks 27,keyed thereto and connected to a comino-n rocker bar 28 for each grate,these rocker bars for the two grates in question being in turn connectedby links 29 to a common operating rod 30 connected to a crank disk 31.This disk is mounted on a shaft 32 suitably journaled in bracketbearings 33 attached to the vertical wall 3l; of the drier casing. Theshaft 32 carries on its other end a. crank disk 312L which, by means ofa rod 3ft, links 29, rocker bars 28a and cranks 27u, all disposed on theopposite side of the drier from thesimilarly numbered parts firstdescribed, will serve operate the segments not shown connected to bars23 in Fig. 2. rlhe crank pins on the disks 31 and 312L are set 180Oapart thus giv ing the adjacent segments in a grate equal but reverseoscillatory motion. The shaft has fast thereon a sprocket gear 35driven. by a sprocket chain from any suitable source of power. The shaftalso has fast 'thereon a smaller sprocket gear 3'? which drives by meansof a chain 38 to a shaft (not shown) corresponding to 32 and controllingoperating mechanism, similar to that described, for controlling thegrate segments of `the two upper grates. @n one of the segment trunmonsof the lower grate l key a4 crank 39, which by a rod 4l() is connectedto a crank 41 fast on the trunnion of the segment disposed at the bottomof the chute 22 so as to oscillate said segment with the other segments.

ln operation, assuming the apparatus is drying wet coal from a washer,the coal is fed through the chute 8 and comes to rest on the adjacentsegment of the upper grate. The blower 3 is started and forces the hotgases under pressure into the casing. The grate operating mechanism isstarted up and as the adjacent grate sections oscillate in oppositedirection, the coal is fed slowly forward across the upper grate, thenfalls through the chute 19 and is fed back and forthiacross the casinguntil inallyl delivered intermittently by the grate segment at thedischarge end of the hopper 22. The stock is held in position in each ofthe transter hoppers so as to seal them and the gases .must thereforepass up through the slots 1 3 of the grate segments and through the bedof the coal resting thereon and in thus passing the coal is graduallyand eectively dried before it is discharged into the hopper whence itpasses by the chute 24 to the pulverizing mill, and having been broughtto the requisite state of ineness is blown off through pipe 2G anddelivered to the combustion chamber or other suitable point of use orstorage. The movement of the grates prevents the checking or cloge gingof the wet stock and keeps it in motion and in a relatively thin sheetthrough which the hot gases under pressure can be forced. The advantageof blowing the hot gases in under pressure is that l thereby obtain aslight pressure within the casing which will prevent the ingress of airthat would be dangerous where fuel is being dried as it might furnishthe necessary oXygen for an explosion.

lll)

Obviously the shape of the drier and the character of the grates may hevaried according to the duty required or the character of stock to hehandled. By varying the speed of rotation of the crank disks, or theradii of the crank pins, either or both, the rate of feed can be variedand the number of grates can be increased or decreased according as thecharacter of the product to be dried may require.

lfithout intending to limit myself to the details of construction shown,What claim, is

l. ln a Waste heat drier, a casing having rocking grate means to passthe products to be dried back and forth across the casing, and means topass hot gases upwardly through the moving layers of stock.

2. A Waste heat drier comprising a. drier casing, grates arranged atdifferent levels in the casing, means to feed the Wet stoclr to theupper grate, means to oscillate the grates to eifect a positive feed ofthe stock thereon transversely of the casing, and means to pass hotgases through the grates.

3. A Waste heat drier in accordance with claim 2, in Which a chute isprovided to transfer the stock from each grate to the next lower grate,said grates being disposed to seal with the descending stock theirrespective feed chutes.

4. ln a Waste heat drier having a top stock inlet, a bottom stock inlet,means to force hot gases into the lower portion of the casing, gratesdisposed across the casing at different levels, each grate comprisingsegments having a foraminous stock support ing face terminating in anarcuate guard. means to oscillate adjacent segments in oppositedirections to effect transverse feed of the stock across the grates.

5. A drier in accordance With claim 4, in Which the segments areprovided With trunnions projecting Without the casing, the alternatetrunnions on one side being connected for joint operation and the otheralternate segment trunnions being connected for joint operation on theother side of the machine, and operating mechanism to oscillate saidgroups of trunnions in opposite directions.

In testimony whereof I affix my signature.

MARTIN J. LIDE.

l/Vitn'ess NoMm WELSH.

